How to check if a JavaScript object is an array?
This video show you how to check if a JavaScript object
is an array
.
Code
let names = ["samy", "trisa", "kim"];Array.isArray(names)Array.isArray("a")Array.isArray(undefined)Array.isArray(null)Array.isArray({"a": 123})typeof names === "object"
Full Transcript
Our goal today is to find out if a given object is an array. Let's say we have a variable called names
whose value is an array containing strings.
Let those strings be sammy
, trisa
and kim
. Now arrays in JavaScript have a method called isArray()
, which determines if the value pass to it as an
argument is an array. So to check if names is an array, we call array.isArray()
and pass names
as argument. As you can see, it returns true
.
If we want to check for a string, a
it returns false
. For undefined
values, it returns false
and same for null
values. Now, if you pass an object
containing the key value pair, it does return false
. Often this confusion stems from the fact that arrays are objects, so to be able to check if a
given object is an array, you should always use array.isArray()
method.